Flexible authentication solution for Rails with Warden

 Devise is Rack based, a MVC solution based on Rails engines, allows one to
 have multiple roles (or models/scopes) signed at the same time, based on a
 modularity concept. It is composed of 12 modules: Database Authenticable,
 Token Authenticable, Omniauthable, Confirmable, Recoverable, Registerable,
 Rememberable, Trackable, Timeoutable, Validatable and Lockable.
 There are a number of extensions to be found at the github homepage of
 devise.